Catheter apparatuses, systems, and methods for renal neuromodulation

Abstract

Catheter apparatuses, systems, and methods for achieving renal neuromodulation by intravascular access are disclosed herein. One aspect of the present application, for example, is directed to apparatuses, systems, and methods that incorporate a catheter treatment device comprising an elongated shaft. The elongated shaft is sized and configured to deliver an energy delivery element to a renal artery via an intravascular path. Thermal or electrical renal neuromodulation may be achieved via direct and/or via indirect application of thermal and/or electrical energy to heat or cool, or otherwise electrically modulate, neural fibers that contribute to renal function, or of vascular structures that feed or perfuse the neural fibers.

We claim: 
     
       1. A catheter apparatus for intravascular renal neuromodulation, comprising:
 an elongated shaft extending along an axis, the elongated shaft comprising a proximal portion and a distal portion, the distal portion including an elongate first flexure zone, a second flexure zone distal of the first flexure zone, and a third flexure zone adjacent to and extending distally beyond the second flexure zone; 
 an energy delivery element carried by and extending distally beyond the third flexure zone, wherein the energy delivery element is configured to contact an intravascular tissue surface and deliver energy to renal nerves positioned adjacent to the intravascular tissue surface; and 
 a control element coupled to the second flexure zone; and 
 an active cooling element comprising an infusion port in the energy delivery element, and wherein the infusion port is in fluid communication with a thermal fluid infusion source, 
 wherein—
 the control element is configured to apply a first force to the second flexure zone to control motion of the energy delivery element in a plane including the axis and position the energy delivery element in contact with the intravascular tissue surface; 
 the energy delivery element is configured to apply energy via the intravascular tissue surface to ablate the renal nerves; and 
 the active cooling element is configured to remove heat from the energy delivery element. 
 
 
     
     
       2. The catheter apparatus of  claim 1 , further comprising a temperature sensor coupled to the energy delivery element. 
     
     
       3. The catheter apparatus of  claim 2 , further comprising a feedback control system configured to alter the removal of heat by the active cooling element in response to the monitored temperature. 
     
     
       4. The catheter apparatus of  claim 1  wherein the energy delivery element and active cooling element together comprise an irrigated electrode. 
     
     
       5. The catheter apparatus of  claim 4  wherein the irrigated electrode comprises six infusion ports in fluid communication with a thermal fluid infusion source. 
     
     
       6. The catheter apparatus of  claim 4  wherein the irrigated electrode comprises a drilled interior portion configured to accept a fluid supply lumen. 
     
     
       7. The catheter apparatus of  claim 4  wherein the irrigated electrode comprises a plurality of laser-cut apertures. 
     
     
       8. The catheter apparatus of  claim 4  wherein the irrigated electrode comprises helical shape wound around a thermal fluid infusion source. 
     
     
       9. The catheter apparatus of  claim 4  wherein the irrigated electrode comprises a plurality of braided filaments and interstitial spaces among the filaments.